Iodine is one of the oldest and best biocidal agents known, being effective against Gram Positive and Gram Negative bacteria, fungi, spores and viruses. Such knowledge of the disinfecting properties of iodine has given rise to a variety of uses whereby iodine, per se, or as complexed with other materials, is used for those properties. When complexed a sustained release reservoir of iodine is provided.
While the biocidal properties of iodine, a non-metallic, essential element, have been known since the early nineteenth century, iodine does present known difficulties in its use. Despite the fact that iodine reacts with both living and dead microorganisms, it does possess properties that are unsuitable for practical application. Thus, iodine has an unpleasant odor and in contact with the skin stains the skin with an intensive yellow-brown color. When used in laundry in the presence of starch, it causes blue stains and will combine with iron and other metals. Because its solutions are not stable, it irritates animal tissue and is a poison. When brought into direct contact with open wounds, iodine toxicity may occur. Thus, the use of iodine directly for its decontaminating characteristic has been relegated to unusual circumstances and has given rise to compositions known as iodophors.
An iodophor may be defined as a complex of iodine in ionic or molecular form or both with a carrier that serves to increase the solubility of iodine in water and also provides a reservoir of iodine for a controlled and sustained release over time. There are two categories of iodophors, water soluble and water insoluble. An example of a water soluble iodophor is the polyvinylpyrrolidone-iodine complex widely used as a germicidal solution. An example of a water insoluble iodophor is polyvinylalcohol sponge complexed with iodine which can be used to wipe down and disinfect hard surfaces.
In the case of water soluble iodophors one obtains a reduction in the concentration of free available iodine in water as a result of the formation of micellar aggregates with the simultaneous reduction in the disadvantages of iodine per se, i.e., its unpleasant odor, irritation and staining of tissue, and corrosion of metal surfaces. An important factor in creating an iodophor is that one wishes to keep the concentration of free iodine in the solution as low as possible; to be effective.
With respect to specific water-insoluble iodophors and those formed with neutral polymers, it is disclosed in U.S. Pat. No. 5 4,888,118 to Barnes et al. that nylon-4 complexed with iodine may be used for the decontamination of water. In that patent it is disclosed that the use of polypyrrolidone, also known as nylon-4, readily complexes with iodine. Thus, Barnes et al. disclose a water purification process and apparatus whereby the water is first subjected to contact either with iodine or a nylon-4 iodine complex. Sufficient time is allowed for the iodine to destroy microbial organisms present. Then, in another treatment area, the water that has been subjected to iodine treatment is contacted with nylon-4 in a form which provides maximum surface area, and free iodine in the water complexes with the nylon-4 thereby to remove such free iodine and result in water that is potable and decontaminated, despite its prior treatment with iodine.
While the complexing of nylon-4 with iodine is thus known, to the best of our knowledge it is not known whether nylon-4 exhibits properties which, in the Barnes et al. or another setting, will be the most efficacious polymer in providing iodine or iodine-based germicides. In the particular use to which Barnes et al. have put nylon-4, i.e., water purification and subsequent removal of iodine from the water, nylon-4 is certainly of sufficient complexing power as to provide an efficacious iodophor. However, when an iodophor is to be used in order to apply a dressing to a wound, such that the release of an iodine compound or ion for its germicidal properties over a long period of time is desirable, it is now been found that nylon-4 is most certainly not the most effective polymer for forming such an iodophor.
Indeed, quite surprisingly, it is now been found that nylon-4,6 is a superior polymer for forming an iodophor based on the two properties that are most desirable in such a dressing, or allied use. Thus, nylon-4,6 provides for the slow, measured release of iodine compositions from the iodophor into the area to be cleansed. Unexpectedly, nylon-4,6 has been found superior to nylon-6 and nylon-6,6 in this regard, although those polymers as well have been found to be superior to nylon-4 in forming an iodophor with a slow, sustained release of the iodine compounds that have germicidal activity. Further, other natural and synthetic fibers, i.e., wool, a protein fiber, nylon, and other polyamides, may possess advantageous properties when used as iodophors.